Disinformation as a result of epistemic error is
an issue in hydrological modelling. In particular the way in
which the colour in model residuals resulting from epistemic
errors should be expected to be non-stationary means that
it is difficult to justify the spin that the structure of residuals
can be properly represented by statistical likelihood functions.
To do so would be to greatly overestimate the information
content in a set of calibration data and increase the
possibility of both Type I and Type II errors. Some principles
of trying to identify periods of disinformative data prior
to evaluation of a model structure of interest, are discussed.
An example demonstrates the effect on the estimated parameter
values of a hydrological model.